1. Field of the Invention
The present invention relates to a reactor system for generating electricity, more precisely a public acceptable simple water-cooled reactor system for generating electricity.
2. Description of the Related Art
Because of the nuclear accident that happened in Fukushima, Japan, in Mar. 11, 2011, the public deeply suspects the safety of nuclear power plant and accordingly efforts have been made to increase safety of the conventional nuclear power plant. Most of the nuclear reactors in the world including the reactor of Japan that had accident are water-cooled reactors. The water-cooled reactor uses water as a coolant in the reactor core, which is exemplified by pressurized water reactor, pressurized heavy water reactor, and boiling water reactor, etc. The important task to increase safety of such water-cooled reactor is to remove decay heat that is constantly generated by radioactive decay of a fission product after the reactor is stopped. To prepare the situation, an emergency core cooling system is equipped in the water-cooled reactor.
Korean Patent No. 10-0668048 describes the system for cooling the exterior wall of a reactor vessel and the method thereof. According to the document, the system contains at least one of pumps to circulate cooling water.
That is, like the system described in the prior art, a safety system so far has depended on the active component that is run by electric power. So, if electric power is lost, all the safety system including such an active component is useless, which has been witnessed in Japan nuclear disaster. Since then, studies have been actively undergoing on the safety system that can remove decay heat generated in the reactor with passive system based on gravity or natural circulation without using an active component. However, the passive safety system is not a perfect alternative to solve the problem of the recent water-cooled reactor. If electric power is lost and natural disasters such as earthquake attack and thus safety system cannot be used, core meltdown and the exposure to the radioactive material are inevitable. Besides, the addition of a safety system increases the reactor construction costs.
Therefore, it is required to develop a novel public acceptable simple water-cooled reactor that includes an efficient decay heat removal system without any additional equipment of safety system.
In the course of study to develop a public acceptable simple water-cooled reactor that includes a decay heat removal system without any additional safety system, the present inventors established a public acceptable simple water-cooled reactor which is not equipped with an additional safety system or any separate cooling water supply but is able to remove decay heat generated right after the nuclear reactor is stopped only using water in the reactor, when a coolant or electric power is lost by an accident, leading to the completion of this invention.